Steam Metadata Editor is a powerful cross-platform application that lets you edit every single aspect of a Steam App. The Editor features an easy to use GUI that lets you edit the most important aspects of the applications. Anything that you would like to edit that's not possible through the GUI, can be modified through the JSON found in `~/.local/share/Steam-Metadata-Editor/config/modifications.json`.

All the changes are local and are bound to be overwritten by Steam sooner or later. That's why the program keeps track of your changes, and can silently patch them back in if you ask it to do so.